The present invention concerns an engine brake for a multicylinder internal combustion engine.
An engine brake of this generic type is disclosed in European Patent Document EP 0 111 232 A1, in which a master piston in a master cylinder is arranged in a common pump casing for each throttle valve, and generates the opening pressure. This arrangement, however, requires great technical complexity, particularly in manufacture and assembly, because many manufacturing steps are necessary on the pump casing and many individual moving parts have to be installed in it. An object of the present invention is to provide an engine brake of the above mentioned generic type which has a substantially simplified construction requiring lower expenditure and which, in particular, permits a simple control of the opening times of the throttle valves.
This object is achieved in the engine brake according to the invention, in which the hydraulic fluid needed to operate all the throttle valves is pumped, and the pressure necessary in this fluid is generated, by a single element such as, for example, a master piston operating in a master cylinder. In addition, the distribution of the hydraulic fluid to the individual throttle valves takes place by means of an easily manufactured distributor which determines in one working process both the timing and the frequency of the fluid supply to the individual throttle valves, and hence the opening timing and frequency thereof.
In a representative embodiment of the invention, an arrangement is provided which avoids interference with the control system of the exhaust valves and makes the opening times of the throttle valves, independent of the control system for the exhaust valves without further complication. The use of a throttle valve in additional to an exhaust valve, which is opened or closed during braking operation of the internal combustion engine as a function of the pressure difference between the cylinder and the exhaust conduit, is disclosed in German Patent Document DE 30 39 451 A1; however, the opening times of this throttle valve cannot be controlled externally in a specified manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.